System.Globalization.StringInfo.SubstringByTextElements C# (CSharp) Method

        public String SubstringByTextElements(int startingTextElement) {
            // If the string is empty, no sense going further. 
            if(null == this.Indexes) {
                // Just decide which error to give depending on the param they gave us....
                if(startingTextElement < 0) {
                    throw new ArgumentOutOfRangeException("startingTextElement",
                        Environment.GetResourceString("ArgumentOutOfRange_NeedPosNum"));
                }
                else {
                    throw new ArgumentOutOfRangeException("startingTextElement",
                        Environment.GetResourceString("Arg_ArgumentOutOfRangeException"));
                }
            }
            return (this.SubstringByTextElements(startingTextElement, this.Indexes.Length - startingTextElement));
        }

		public void SubstringByTextElements ()
		{
			StringInfo si = new StringInfo ("A\u0330BC\u0330");
			Assert.AreEqual ("A\u0330BC\u0330", si.SubstringByTextElements (0), "#1");
			Assert.AreEqual ("BC\u0330", si.SubstringByTextElements (1), "#2");
			Assert.AreEqual ("C\u0330", si.SubstringByTextElements (2), "#3");
		}